Person tracking robot guidance system

I am trying to come up with an idea to make a robot follow or come to a keychain type of device. Ie my son can carry a key fob and the robot would follow him around like a puppy lol ( I would never attach the fob to the wife's cat ;-) )

My idea so far would be to use an ir led perhaps 38khz strobe and on the robot a receiver mounted on a servo so that it can sweep back and forth allowing it to find this signal and follow it. The receiver would have blinders of some sort to make it directionally sensitive. It would be nice it you were able to use this in a house where line of sight may not always be available... so i may need to add an rf component ...

Does any one have any experience or perhaps a better idea? So far this seems fairly straight forward ...

So far this seems fairly straight forward ...

That's why you have been overwhelmed with the amount of data on how to do this, right?

There have been numerous project discussions about making various "follow me" bots, but most were overly complex and ambitious and pretty much turned into hanger flying sessons. Your project seems fairly simple. There are projects on the net that have small light seeking bots that might make a starting point.

About 30 years ago, Rod Brooks built a hexapod robot with a bank of small directional PIR sensors that could follow after people.

A few weeks ago the Ben Heck Show was about building a rolling luggage robot that would follow its owner.

link to some previous post

Thanks for the input guys ! Lots of great ideas :-)